Enhanced Thermal Stability under DC Electrical Conductivity Retention and Visible Light Activity of Ag/TiO₂@Polyaniline Nanocomposite Film

Ansari, Mohd Omaish,Khan, Mohammad Mansoob,Ansari, Sajid Ali,Raju, Kati,Lee, Jintae,Cho, Moo Hwan American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.11

<P>The development of organic–inorganic photoactive materials has resulted in significant advancements in heterogeneous visible light photocatalysis. This paper reports the synthesis of visible light-active Ag/TiO<SUB>2</SUB>@Pani nanocomposite film via a simple biogenic–chemical route. Electrically conducting Ag/TiO<SUB>2</SUB>@Pani nanocomposites were prepared by incorporating Ag/TiO<SUB>2</SUB> in <I>N</I>-methyl-2-pyrrolidone solution of polyaniline (Pani), followed by the preparation of Ag/TiO<SUB>2</SUB>@Pani nanocomposite film using solution casting technique. The synthesized Ag/TiO<SUB>2</SUB>@Pani nanocomposite was confirmed by UV–visible spectroscopy, photoluminescence spectroscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The Ag/TiO<SUB>2</SUB>@Pani nanocomposite film showed superior activity towards the photodegradation of methylene blue under visible light compared to Pani film, even after repeated use. Studies on the thermoelectrical behavior by DC electrical conductivity retention under cyclic aging techniques showed that the Ag/TiO<SUB>2</SUB>@Pani nanocomposite film possessed a high combination of electrical conductivity and thermal stability. Because of its better thermoelectric performance and photodegradation properties, such materials might be a suitable advancement in the field of smart materials in near future.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-11/am500488e/production/images/medium/am-2014-00488e_0013.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am500488e'>ACS Electronic Supporting Info</A></P>

Electrically conductive polyaniline sensitized defective-TiO₂ for improved visible light photocatalytic and photoelectrochemical performance: a synergistic effect

Ansari, Mohd Omaish,Khan, Mohammad Mansoob,Ansari, Sajid Ali,Cho, Moo Hwan The Royal Society of Chemistry 2015 NEW JOURNAL OF CHEMISTRY Vol.39 No.11

<P>Sulfonated polyaniline@pure-TiO<SUB>2</SUB> (s-Pani@p-TiO<SUB>2</SUB>) and polyaniline@defective-TiO<SUB>2</SUB> (s-Pani@m-TiO<SUB>2</SUB>) nanocomposites were prepared by the <I>in situ</I> oxidative polymerization of aniline in the presence of TiO<SUB>2</SUB> (p-TiO<SUB>2</SUB> and m-TiO<SUB>2</SUB>) nanoparticles followed by sulfonation with fuming sulfuric acid. Defect-induced TiO<SUB>2</SUB> (m-TiO<SUB>2</SUB>) nanoparticles were obtained by an electron beam (EB) treatment of commercial TiO<SUB>2</SUB> (p-TiO<SUB>2</SUB>) nanoparticles. The resulting s-Pani@p-TiO<SUB>2</SUB> and s-Pani@m-TiO<SUB>2</SUB> nanocomposites were characterized by UV-visible diffuse absorbance spectroscopy, photoluminescence spectroscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Polyaniline (Pani) was dispersed uniformly over the defective m-TiO<SUB>2</SUB> surface with intimate contact on the interface to act cooperatively with the deliberately induced defects to achieve remarkably enhanced properties. The s-Pani@m-TiO<SUB>2</SUB> nanocomposite showed better photocatalytic activity and photoelectrochemical performance than s-Pani@p-TiO<SUB>2</SUB> under visible light irradiation, which was attributed partly to the sensitizing effect of Pani, the narrowed band gap of m-TiO<SUB>2</SUB> and the effective interfacial interaction between Pani and m-TiO<SUB>2</SUB>. The electrical conductivity measured using a four-point probe revealed s-Pani@m-TiO<SUB>2</SUB> to have much higher conductivity than s-Pani@p-TiO<SUB>2</SUB>. Therefore, s-Pani@m-TiO<SUB>2</SUB> may be used for a wide range of applications owing to its higher charge mobility and high photocatalytic activity. The proposed methodology can also be a potential route for the development of nanocomposites <I>via</I> EB treatment and can be commercialized.</P> <P>Graphic Abstract</P><P>A proposed scheme for the synthesis of s-Pani@m-TiO<SUB>2</SUB> nanocomposites. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5nj01127b'> </P>

Gold nanoparticles-sensitized wide and narrow band gap TiO₂ for visible light applications: a comparative study

Ansari, Sajid Ali,Khan, Mohammad Mansoob,Ansari, Mohd Omaish,Cho, Moo Hwan The Royal Society of Chemistry 2015 NEW JOURNAL OF CHEMISTRY Vol.39 No.6

<P>Gold nanoparticles (AuNPs)-sensitized wide band gap TiO<SUB>2</SUB> (Au/P-TiO<SUB>2</SUB>) and narrow band gap TiO<SUB>2</SUB> (Au/M-TiO<SUB>2</SUB>) nanocomposites were prepared using an electrochemically active biofilm. The optical and structural properties of the Au/P-TiO<SUB>2</SUB> and Au/M-TiO<SUB>2</SUB> nanocomposites were characterized using standard techniques. The surface plasmon resonance (SPR) absorption characteristics of the AuNPs on the TiO<SUB>2</SUB> surface extended the absorption edge of P-TiO<SUB>2</SUB> and M-TiO<SUB>2</SUB> to the visible light region. The photocatalytic activity of the Au/P-TiO<SUB>2</SUB> and Au/M-TiO<SUB>2</SUB> nanocomposites was evaluated by the photodegradation of methylene blue and methyl orange, and 2-chlorophenol under visible light irradiation, where Au/M-TiO<SUB>2</SUB> nanocomposite exhibited enhanced photocatalytic activity compared to the Au/P-TiO<SUB>2</SUB> nanocomposite and P-TiO<SUB>2</SUB> and M-TiO<SUB>2</SUB> nanoparticles. Furthermore, the higher photoelectrochemical performance of the Au/M-TiO<SUB>2</SUB> nanocomposite compared to the Au/P-TiO<SUB>2</SUB> nanocomposite and P-TiO<SUB>2</SUB> and M-TiO<SUB>2</SUB> nanoparticles further support its higher visible light active behavior under visible light irradiation. The pronounced photoactivities of the Au/M-TiO<SUB>2</SUB> nanocomposite in the visible region were attributed to the interfacial synergistic effects of the two phenomena, <I>i.e.</I> the SPR effect of AuNPs and the defect-induced band gap reduction of M-TiO<SUB>2</SUB> nanoparticles. The present work provides a newer insight into the development of nanocomposites of noble metals and defective metal oxides with high efficiency in the field of visible light-induced photoactivity.</P> <P>Graphic Abstract</P><P>Photocatalytic degradation of dyes and organic compounds by Au/P-TiO<SUB>2</SUB> and Au/M-TiO<SUB>2</SUB> nanocomposites under visible light irradiation. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5nj00556f'> </P>

Highly photoactive SnO₂ nanostructures engineered by electrochemically active biofilm

Ansari, Sajid Ali,Khan, Mohammad Mansoob,Omaish Ansari, Mohd,Lee, Jintae,Cho, Moo Hwan The Royal Society of Chemistry 2014 NEW JOURNAL OF CHEMISTRY Vol.38 No.6

<P>This paper reports the defect-induced band gap narrowing of pure SnO<SUB>2</SUB> nanostructures (p-SnO<SUB>2</SUB>) using an electrochemically active biofilm (EAB). The proposed approach is biogenic, simple and green. The systematic characterization of the modified SnO<SUB>2</SUB> nanostructures (m-SnO<SUB>2</SUB>) revealed EAB-mediated defects in the pure SnO<SUB>2</SUB> nanostructures (p-SnO<SUB>2</SUB>). The modified SnO<SUB>2</SUB> (m-SnO<SUB>2</SUB>) nanostructures in visible light showed the enhanced photocatalytic degradation of <I>p</I>-nitrophenol and methylene blue compared to the p-SnO<SUB>2</SUB> nanostructures. The photoelectrochemical studies, such as the electrochemical impedance spectroscopy and linear scan voltammetry, also revealed a significant increase in the visible light response of the m-SnO<SUB>2</SUB> compared to the p-SnO<SUB>2</SUB> nanostructures. The enhanced activities of the m-SnO<SUB>2</SUB> in visible light was attributed to the high separation efficiency of the photoinduced electron–hole pairs due to surface defects mediated by an EAB, resulting in a band gap narrowing of the m-SnO<SUB>2</SUB> nanostructures. The tuned band gap of the m-SnO<SUB>2</SUB> nanostructures enables the harvesting of visible light to exploit the properties of the metal oxide towards photodegradation, which can in turn be used for environmental remediation applications.</P> <P>Graphic Abstract</P><P>This paper reports the defect-induced band gap narrowing of pure SnO<SUB>2</SUB> nanostructures (p-SnO<SUB>2</SUB>) using an electrochemically active biofilm (EAB). <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c3nj01488f'> </P>

Simultaneous sulfur doping and exfoliation of graphene from graphite using an electrochemical method for supercapacitor electrode materials

Parveen, Nazish,Ansari, Mohd Omaish,Ansari, Sajid Ali,Cho, Moo Hwan The Royal Society of Chemistry 2016 Journal of Materials Chemistry A Vol.4 No.1

<▼1><P>Doping with heteroatoms has become a significant strategy for modifying the electronic properties and enhancing the electrochemical properties of graphene (GN).</P></▼1><▼2><P>Doping with heteroatoms has become a significant strategy for modifying the electronic properties and enhancing the electrochemical properties of graphene (GN). In this study, an environmental friendly, economical and facile one pot electrochemical method was developed to synthesize sulfur-doped graphene (S-GN). Sodium thiosulphate (Na2S2O3), in addition to acting as a sulfur source, also catalyzed the exfoliation process, resulting in sulfur-doped GN structures. The exfoliation of graphite to GN and sulfur (S) doping occurred simultaneously resulting in well dispersed S-GN frameworks. Transmission electron microscopy and high-resolution transmission electron microscopy revealed the presence of the heteroatom in S-GN, and X-ray photoelectron spectroscopy confirmed the high S content (3.47%), as well as the existence of high-quality sulphureted species (mainly as C–S–C–). The incorporation of S species in GN during the exfoliation process modified the surface chemistry of carbon in the GN. The electrochemical performance of the as-prepared S-GN electrode exhibited a high specific capacitance of 320 F g<SUP>−1</SUP> at a current density of 3 A g<SUP>−1</SUP> and excellent cycling stability up to 1500 cycles as well as high energy density of 160 W h kg<SUP>−1</SUP> at a power density of 5161 W kg<SUP>−1</SUP> in an aqueous electrolyte.</P></▼2>

Route to High Surface Area, Mesoporosity of Polyaniline–Titanium Dioxide Nanocomposites via One Pot Synthesis for Energy Storage Applications

Parveen, Nazish,Ansari, Mohd Omaish,Cho, Moo Hwan American Chemical Society 2016 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.55 No.1

<P>This paper reports the synthesis of mesoporous polyaniline-titanium dioxide (Pani-TiO2) nanocomposites via a one pot approach in the presence of aniline and titanium iso-propoxide precursor under ice bath conditions. Scanning and transmission electron microscopy showed that the Pani-TiO2 was mesoporous in nature. BET analysis revealed the Pani-TiO2 to have a 2-fold higher surface area than Pani. The shift of the peaks in the FTIR and XRD pattern showed that TiO2 had perfectly intercalated into the Pani matrix, which suggests a strong interaction between Pani and TiO2. The electrochemical properties of Path and the mesoporous Pani-TiO2 were examined by cyclic voltammetry and charge/discharge studies. The mesoporous Pani-TiO2 electrode exhibited a high specific capacitance of 935 F g(-1) at 1 A g(-1) current density. The mesoporous Pani-TiO2 displayed excellent cyclic stability up to 2000 cycles and delivered a high energy density of 94.8 Wh kg(-1) at a 977 W kg(-1) power density.</P>

Visible light-induced enhanced photoelectrochemical and photocatalytic studies of gold decorated SnO₂ nanostructures

Khan, Mohammad Mansoob,Ansari, Sajid Ali,Khan, Mohammad Ehtisham,Ansari, Mohd Omaish,Min, Bong-Ki,Cho, Moo Hwan The Royal Society of Chemistry 2015 NEW JOURNAL OF CHEMISTRY Vol.39 No.4

<P>This paper reports a novel one-pot biogenic synthesis of Au–SnO<SUB>2</SUB> nanocomposite using electrochemically active biofilm. The synthesis, morphology and structure of the as-synthesized Au–SnO<SUB>2</SUB> nanocomposite were in-depth studied and confirmed by UV-vis spectroscopy, photoluminescence spectroscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. It was observed that the SnO<SUB>2</SUB> surface was decorated homogeneously with Au nanoparticles. The photoelectrochemical behavior of the Au–SnO<SUB>2</SUB> nanocomposite was examined by cyclic voltammetry, differential pulse voltammetry, electrochemical impedance spectroscopy, and linear sweep voltammetry in the dark and under visible light irradiation. Visible light-induced photoelectrochemical studies confirmed that the Au–SnO<SUB>2</SUB> nanocomposite had enhanced activities compared to the P–SnO<SUB>2</SUB> nanoparticles. The Au–SnO<SUB>2</SUB> nanocomposite was also tested for the visible light-induced photocatalytic degradation of Congo red and methylene blue, and showed approximately 10 and 6-fold higher photocatalytic degradation activity, respectively, compared to P–SnO<SUB>2</SUB>. These results showed that the Au–SnO<SUB>2</SUB> nanocomposite exhibits excellent and higher visible light-induced photoelectrochemical and photocatalytic activities than the P–SnO<SUB>2</SUB> nanoparticles, and can be used for a wide range of applications.</P> <P>Graphic Abstract</P><P>Visible light-induced photocatalytic degradation of colored dyes using Au–SnO<SUB>2</SUB> nanocomposite. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4nj02245a'> </P>

Biogenic Fabrication of Au@CeO₂ Nanocomposite with Enhanced Visible Light Activity

Khan, Mohammad Mansoob,Ansari, Sajid Ali,Ansari, Mohd Omaish,Min, B. K.,Lee, Jintae,Cho, Moo Hwan American Chemical Society 2014 The Journal of Physical Chemistry Part C Vol.118 No.18

<P>This study reports a biogenic approach to the synthesis of Au@CeO<SUB>2</SUB> nanocomposite using electrochemically active biofilms (EABs) in water under normal pressure and 30 °C. This work presents the results of extensive morphological, structural, optical, visible light photoelectrochemical and photocatalytic studies of Au@CeO<SUB>2</SUB> nanocomposite. The presence of a large number of interfaces between Au nanoparticles and CeO<SUB>2</SUB> for charge transfer is believed to play a key role in enhancing the optical and visible light photoelectrochemical and photocatalytic performance of Au@CeO<SUB>2</SUB> nanocomposite. The enhanced visible light degradation of methyl orange and methylene blue by Au@CeO<SUB>2</SUB> nanocomposite was much higher than that by pure CeO<SUB>2</SUB>. The reusability, stability, and other results suggests that the Au@CeO<SUB>2</SUB> nanocomposite could be exploited as potential candidates for visible light photocatalysis, photovoltaic, and photoelectrochemical devices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2014/jpccck.2014.118.issue-18/jp500933t/production/images/medium/jp-2014-00933t_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp500933t'>ACS Electronic Supporting Info</A></P>

Dodecylbenzenesulfonic acid micelles assisted in situ preparation and enhanced thermoelectric performance of semiconducting polyaniline–zirconium oxide nanocomposites

Tarique Anwer,Faiz Mohammad,Mohd Omaish Ansari 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.5

Herein, we report in situ preparation of dodecylbenzenesulfonic acid (DBSA) micelles assisted polyaniline (Pani)/zirconium oxide (ZrO2) nanocomposites (Pani/ZrO2) by using K2S2O8 as an oxidizing agent. Thus prepared nanocomposites were characterized by SEM, FTIR, XRD and UV–vis spectropho-tometry. DBSA acted as dopant/surfactant, and the incorporation of ZrO2 nanoparticles improved the stability, electrical and thermal properties of nanocomposites. From the results of UV–vis absorbance it was observed that Pani/ZrO2 nanocomposite was more stabilized under UV light than Pani. DC electrical conductivity retention was studied by isothermal and cyclic ageing techniques and was observed to be better than Pani under ambient environmental conditions.

Phenol removal and hydrogen production from water: Silver nanoparticles decorated on polyaniline wrapped zinc oxide nanorods

Asim Jilani,Mohammad Omaish Ansari,Ghani ur Rehman,Muhammad Bilal Shakoor,Syed Zajif Hussain,Mohd Hafiz Dzarfan Othman,Sajid Rashid Ahmad,Mohsin Raza Dustgeer,Ahmed Alshahrie 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.109 No.-

The toxic and carcinogenic organic compounds discharge from industries, contaminate the natural reservoirsof water and air which eventually pose a global threat not only to the aquatic life but also to thehumanity. Herein, ternary nanocomposites of silver-nanoparticle (AgNPs)-decorated on polyaniline(Pani)-wrapped zinc oxide nanorods (AgNPs@Pani/ZnO) were prepared via a facile approach. Thenanocomposite degraded 97.91% phenol with an optimized dosage and concentration of H2O2. Moreover, the apparent rate constant for phenol degradation was 3.69 times higher than for pure ZnOnanorods. The hydrogen production from AgNPs@Pani/ZnO was 1.58 and 2.74 times higher than Pani/ZnO and ZnO, respectively. The enhanced phenol degradation and hydrogen production is attributed tothe transfer of holes to the Pani, from which the electrons were transferred to the conduction band ofZnO and eventually to the conduction band of the AgNPs, where they accelerated the redox reactionsfor rapid photolysis of water and phenol. The concentration of the catalyst dosage affected the rate ofphenol degradation. Further, response surface methodology was also applied in order to design 13 setsof random experiments in which the catalyst dosage and degradation time were varied to predict thephenol degradation.